Improvement in tanning



UNrTED STATES PATENT OFFICE.

ROSWELL CRANE AND WM. BALDWIN, OF ANAMOSA, IOWA.

IMPROVEMENT IN TANNING.

Specification forming part of Letters Patent No. 30,390, dated October16, 1860.

cess until the tanning of the leather is completed.

To enable others skilled in the art to fully understand and use ourinvention, we will proceed to describe it.

The hides are first prepared in the usual way, and they are now treatedwith a solution of terra-japonica in lye, as follows: One gallon (1gal.) of lye of sut'ficient strength to bear up an egg, with one gallon(l gal.)ot' water, are put into aniron kettle, and twenty pounds (20lbs.) of terra-japonica are dissolved in this liquid by a gentle heat.When thoroughly dissolved the mixture is put into the vat and dilutedwith ninety gallons (90 gals.) of water. This liquor is sufficient fortwenty-five sides of hides, which are put into the vat, the whole beingwell stirred. On every third day we add ten pounds (10 lbs.) ofterra-japonica dissolved in a half-gallon (1} gal.) of lye andsufficient water to keep the hides covered, and this is repeated untilthe hides are two thirds tanned. Sufficient terra -japonica is nowadded, dispensing with thelye, until the hides are well tanned, when theleather is finished in the usual manner.

By thus combining lye with terra-japonica for tanning upper-leather weobtain a leather whose body is firmer and more impervious to water, witha smoother surface and higher finish, than can be obtained by any otherprocess, bark not excepted; and in tanning sole-leather the lye useddoes not affect the glutinous substance of the hide, audit gives agreater weight to the leather. The lye employed according to our processraises the hide suificiently for speedy tanning, thereby dispensing withall acids or salts which are generally usedin other processes.

What we claim as new, and desire to secure by Letters Patent, is

The process of tanning leather herein shown and described, consisting inthe use of a compound composed of terra-japonica and lye, in theproportions and manner herein specified.

ROSWELL CRANE. WM. BALD WIN.

